Vacuum switch having arcuate tubular contacts actuated by internal fluid pressure



2,993,971 cTs July 25, 1961 H. M. PFLANZ VACUUM SWITCH HAVING ARCUATE TUBULAR CONTA ACTUATED BY INTERNAL FLUID PRESSURE 2 Sheets-Sheet 1 Filed Dec. 19, 1958 y 5, 1961 H. M. PFLANZ 2,993,971

VACUUM SWITCH HAVING ARCUATE TUBULAR CONTACTS ACTUATED BY INTERNAL FLUID PRESSURE Filed Dec. 19, 1958 2 Sheets-Sheet 2 VACUUM SWITCH HAVING ARCUATE TUBULAR CONTACTS ACTUATED BY INTERNAL FLUID PRESSURE Herbert M. Pflanz, Roslindale, Mass, assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis.

Filed Dec. '19, 1958, Ser. No. 781,671 4 Claims. (Cl. 200-144) This invention relates to electric devices employing a movable element therein and more particularly to a new and improved vacuum switch employing relatively movable cooperating contacts which are actuated by fluid under pressure.

Heretofore electric devices such as vacuum switches employed a plurality of sliding members for controlling the axial and lateral movement of the movable contacts. These sliding members not only are costly to manufacture but require bearings and make the Vacuum switch highly susceptible to shock and vibration. Further, the axial movement of a movable contact extending through a bellows attached in fluid tight engagement to the walls of a vacuumized envelope makes the envelope susceptible to air leakage and increases the possibility of a short life for the switch.

In accordance with the invention claimed there is provided a new and improved electrical device such as an electric switch, a vacuum condenser, or an electron discharge device comprising in combination an envelope and a hollow member extending within the envelope. The hollow member employs a deformable portion arranged within the envelope for movement from a first position to a second position upon application of fluid under pressure to the interior of the member. The deformable portion returns to its first position upon predetermined reduction of fluid pressure therewithin. As set forth in some of the claims the deformable portion of the hollow member may comprise one of a pair of cooperating contacts arranged within the vacuumized envelope.

It is, therefore, one object of this invention to provide a new and improved electric device embodying an enclosing envelope in which a hollow member extending therein is caused to deform to perform a useful function.

Another object of this invention is to provide a new and improved electric device of the character described in which one end of a member mounted to extend within a vacuumized envelope is caused to move without any axial movement through the envelope.

A further object of this invention is to provide a new and improved vacuumized electric switch in which a contact mounted for movement within a vacuumized envelope is fixedly attached to the vacuumized envelope at the entrance thereto.

A still further object of this invention is to provide a new and improved vacuumized electric switch in which a hollow contact mounted for movement within a vacuumized envelope is actuated by fluid under pressure forced within the contact from outside of the envelope.

A still further object of this invention is to provide a new and improved vacuum switch in which a hollow deformable contact fixedly attached to and extending within a vacuumized envelope for movement therein is cooled by the fluid under pressure used therein for deformation thereof.

Objects and advantages other than those set forth will be apparent from the following description when read in connection with the accompanying drawings, in which:

FIG. 1 is an elevational view partly in axial section of a vacuum switch embodying the invention;

FIGS. 2 through 9 are modifications of the contact nited States Patent "ice structure illustrated in FIG. 1 each shown in a vacuumized envelope;

FIG. 10 is a cross sectional view of FIG. 9 taken along the line XX; and

FIG. 11 is an enlarged cross sectional view partly in section of a further modification of the deformable contact structure shown in FIGS. 1 through 10 wherein passages are provided inthe movable contact for continuous fluid flow through the movable contact during actuation thereof.

Referring more particularly to the drawings by characters of reference FIG. 1 illustrates an electric switch 15 comprising a cylindrical envelope 16 which may be formed, for example, of a suitable vitreous material. One end of envelope 16 is provided with an annular rim 17 to which is fixedly secured in gas tight connection thereto one end of a ring or flange 18. A metallic cap 19 is sealed throughout its edge to the other end of flange 18 in the manner shown in FIG. 1. The cap 19 may be reentrant as shown or may be relatively flat or even protruding, if desired.

Base 20 of cap 19 supports a contact mounting or bushing 21 to which is secured one end of a fixed contact member 22. Contact member 22 is arranged to extend longitudinally of envelope 16 and is substantially rigidly supported so as to restrict longitudinal or lateral movement thereof.

The opposite end of envelope 16 is provided with an annular rim 24 to which is fixedly secured in a vacuum tight connection one end of a ring or flange 25. A metallic cap 26 is sealed throughout its edge to the other end of flange 25. Cap 26 may be reentrant as shown or may be relatively flat or even protruding, if desired. Base 27 of cap 26 supports a contact mounting or bushing 28 to which is fixedly secured a hollow fluid conducting contact member 30. Contact member 30 is arranged to extend longitudinally of the axis of envelope 16 and is substantially rigidly supported so as to restrict longitudinal or lateral movement at the point it enters envelope 16. Cap 26 supports a tubular venting passage 31 through which envelope 16 is evacuated and sealed oil in the usual way.

In accordance with the invention claimed the hollow, tubular, curved contact member 30 comprises a relatively fixed portion 32 and a relatively movable or deformable arcuate portion 33. The deformable arcuate portion 33 is normally curved causing a closed end arcing tip 34 of the contact member 30 to be biased into engagement with an arcing tip 35 of the stationary con tact member 22. When suitable fluid under pressure, such as air, is applied to the open end 36 of the hollow, tubular contact member 30 outside of the confines of envelope 16 the deformable arcing tip 33 is flexed or actuated for movement through an arcuate path from a first curved position in biasing contact engagement with contact member 22 to a second substantially straight contact disengaging position spaced from contact member 22. Contact member 30 remains in contact open position with its contact tip 34 separated from contact tip 35 until the pressure in tubular contact member 30 is sufliciently reduced to cause the deformed arcing tip 33 to resume its arcuate geometrical configuration thereby returning to contact engaging position with contact member 22.

The use of the Bourdon tube principle of straightening out a curved section of a hollow tube closed at one end by the application of fluid under pressure thereto makes it possible to interrupt high voltage circuits in a vacuumized envelope with a small contact gap of about 1 kv. per mil (or more) without requiring axial movement of the movable contact member through the vacuumized envelope. As noted from FIG. 1 of the drawing cooperating contact members 22 and 30 perform their opening and closing switching function without the use of a flexible seal such as a bellows or diaphragms. No sliding, movable contacts are required. Thus, the prior art bearings, guiding means and the associated shunt current conducting braids are eliminated.

In order to control the arcing products emitted upon separation of the engaging surfaces of contact members 22 and 30 a cylindrical cup shaped tube or shield 37 is provided around and spaced from contact member 22. Shield 37 is arranged to extend beyond the adjacent ends of the contact members so as to surround at least a part of contact member 36 when in contact engaging position. Shield 37 may be formed of glass or any suitable metallic or nonmetallic material.

FIG. 2 illustrates diagrammatically a modification of the invention shown in FIG. 1 wherein two hollow, tubular contact members '49 and 41 are mounted within any suitable metallic or vacuumized envelope, for example, envelope '42. One end of envelope 42 is provided with an annular rim 43 to which is fixedly secured in gas tight connection thereto the rim of an enclosing cap 44. Cap 44 supports contact mountings o-r insulating bushings 45 and 46 for contact members 40 and 41, respectively. Contact members 40 and 41 are each provided with deformable arcuate portions 47 and 48, respectively, which are normally curved to cause their closed end arcing tips '49 and 50 to be biased into engagement with each other. When suitable fluid under pressure is applied to the orifices 38 and 39 of contact members 40 and 41 outside of envelope 42 the deformable portions 47 and 48 are straightened out causing contact tips 49 and 50 to separate and the contact members to be actuated from contact closed to contact open positions.

FIGS. 3 through 9 illustrate further modifications of the invention shown in FIG. 1 wherein like parts are provided with the same reference characters. In FIG. 3 the stationary and movable cooperating contact members 52 and 53, respectively, are mounted within a suitable vacuumized envelope 54. Envelope 54 comprises a pair of rims 55 one arranged at each end thereof to which are fixedly secured in gas tight connection a pair of envelope sealing caps 56. Bushings 57 support contact members 52 and 53 within envelope 54. As shown in FIG. 3 contact 53 is a hollow, tubular closed end member having an arcuate deformable portion 58 soformed that when the pressure inside of it is normal or of atmospheric value the arcing tips 59 and -60 of contact members 52 and 53 are spaced apart in contact open position. When fluid under pressure is applied to orifice 61 of contact member 53 outside of envelope 54 the deformable port-ion 58 of contact member 53 is deflected causing cont-act tip 60 to engage contact tip 59 in circuit closed position.

FIG. 4 illustrates a modification of the structures shown in FIGS. 2. and 3. Contact members 41} and 41 are mounted to extend within opposite ends of envelope 54 in contact closed position and when fluid under pressure is applied to the inside of each hollow, tubular contact member the deformable portions are separated and move to circuit open position.

FIG. illustrates a further modification of FIG. 3 wherein the stationary contact member 52 of FIG. 3 is replaced with a deformable movable tubular contact member 63 having a closed end deformable portion 64 provided with an arcing tip 65. The cooperating movable, deformable contact members 53 and 63 are so arranged that they are separated when normal or atmospheric pressure exists inside of the deformable portions of these contacts and when fluid under pressure is applied to the interior of contact members 53 and 63 through orifices 61 and 66 outside of envelope 54 the deformable portions 58 and 64 deflect toward each other and contact tips 69 and 65 are biased into firm engagement with each other. Upon a predetermined reduction in pressure inside of the deformable portions of contact members 53 and 63 the members return to their normal contact open position.

FIG. 6 illustrates a further modification of the invention wherein the movable cooperating, hollow, tubular deformable contact members 68 and 69 are each provided with more than one curved deformable portion 70 and 71, respectively. The sinuous shaped contact members are so arranged that the curved portions of each member when deformed by pressure applied therein throught orifices 72 and 73 together cause a substantial axial movement of the contact tips toward each other causing engagement of the arcing tips 74 and 75 of contact members 68 and 69, respectively, to complete an electric circuit therethrough. When the pressure within contact members 68 and 69 are of a predetermined value such as atmospheric pressure the members return to their normal sinuous form in contact open position.

FIG. 7 illustrates a further modification of the invention wherein the movable, deformable, hollow tubular closed end contact member 77 is coiled in such a manner that upon the application of fluid under pressure to orifice 78 the curved portion 79 of contact member 77 deforms and causes contact tip 89 to move axially and through an arcuate path from contact closed to contact open position.

FIG. 8 illustrates a further modification of FIG. 7 wherein a pair of cooperating contacts 83 and 84 each comprise a coiled, hollow, tubular closed end contact member which is deformable upon the application of fluid pressure to the inside thereof through orifices 85 and 86 to cause the coil portions of each of the members to rotate and move axially. This action causes the contact arcing tips 87 and 88 of contact members 83 and 84, respectively, to move from contact closed to contact open positions.

FIGS. 9 and 10 illustrate a further modification of the invention wherein a double coiled deformable, hollow, tubular conductive member 91 is arranged to extend within one end of envelope 54 with the open and closed ends 92 and 93 of member 91 secured to cap 56. An electrically conductive portion 94 of member 91 makes and breaks contact with electric conductors 95 and 96 to form an electrical connection therebetween. Conductors 95 and 96 are arranged to extend within the other end of envelope 54 in fluid tight connection therewith. When the pressure Within member 91 is of substantially atmospheric value the current conducting portion 94 thereof is arranged between conductors 95 and 96 in a nonconducting position (note FIG. 10). However, when pressure is applied to the inside of member 91 it deforms and rotates portion 94 to engage at different points thereon conductors 95 and 96 to form an electrical connection therebetween.

FIG. 11 illustrates a fluid conducting hollow, tubular deformable movable contact member 97 which may be used in place of any one of the deformable movable contact members shown in FIGS. 1-10. Contact member 97 comprises a closed end outer deformable hollow, tubular portion or member 98 having an arcing tip 99 arranged at the closed end thereof and a coaxially arranged inner deformable hollow, tubular member 100 extending with member 98. The end 101 of member 100 near the arcing tip 99 is open and spaced from the closed end of member 98 a sufficient distance to permit the fluid under pressure flowing into member 93 between member 100 and the inner walls of member 98 to flow into member 100 through its open end 101 and out of contact 97 to atmosphere, if so desired. This type of structure makes it possible to cool the arcing tip of the movable contact member at the same time that it is being actuated from one circuit position to another circuit position. Although the inner member 100 is shown as being coaxially arranged within member 97 it is Within the scope of this invention to position member 100 any place within and longitudinally of member 98. It is also within the scope of this invention to provide a hollow, tubular deformable contact member of any suitable cross sectional geometrical configuration, however, it has been found that an oval cross sectional configuration deforms satisfactory unidirectional under the disclosed conditions.

Although but a few embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

Having now particularly described and ascertained the nature of my said invention and the manner in which it is to be performed, I declare that what I claim is:

1. An electric device comprising a vacuumized envelope, a pair of spaced contacts mounted to extend through openings within said envelope, each of said contacts being in vacuum tight seal to said envelope, a bridging contact comprising a hollow member having a closed end coiled contact engaging portion within said envelope, said coiled contact engaging portion being rotated from one contact position to another contact position, and means for applying fluid under pressure to the interior of said member outside of said envelope for rotating said coiled contact portion and actuating it from said one contact position to said another contact position, said coiled contact portion returning to said one position upon predetermined reduction of fluid pressure within said member.

2. An electric device comprising a vacuumized envelope, a pair of spaced contacts mounted to extend through openings arranged within the same end of said envelope, each of said contacts being in vacuum tight seal to said envelope, a bridging contact extending within another end of said envelope and comprising a hollow member having a closed end coiled contact engaging portion within said envelope, said coiled contact engaging portion being rotated from one contact position to another contact position, and means for applying fluid under pressure to the interior of said member outside of said envelope for rotating said coiled contact portion and actuating it from said one contact position to said another contact position, said coiled contact portion returning to said one position upon predetermined reduction of fluid pressure within said member.

3. An electric device comprising a vacuumized envelope, a pair of spaced contacts mounted to extend through openings arranged within a first end of said envelope, each of said contacts being in vacuum tight seal to said envelope, a bridging contact comprising a doubled coiled deformable hollow member arranged to extend within a second end of said envelope, said coiled member having an open end and a closed end secured to said second end of said envelope, said coiled contact engaging portion being rotated from one contact position to another contact position, and means for applying fluid under pressure to the interior of said member outside of said envelope for rotating said coiled contact portion and actuating it from said one contact position to said another contact position, said coiled contact portion returning to said one position upon predetermined reduction of fluid pressure within said member.

4. An electric device comprising a vacuumized envelope, a pair of spaced contacts mounted to extend through openings within said envelope, each of said con tacts being in vacuum tight seal to said envelope, a bridging contact comprising a hollow member having a closed end coil contact engaging portion within said envelope, a deformable hollow tube coaxially arranged with said member and extending within said portion, said member forming a passage between said tube and the inner walls of said member for conducting fluid under pressure to the closed end of said member and said tube forming a return passage therethrough to atmosphere for the fluid under pressure, said portion being rotated from one contact position to another contact position, and means for applying fluid under pressure to the interior of said member outside of said envelope for rotating said portion and actuating it from said one contact position to said another contact position, said portion returning to said one position upon predetermined reduction of fluid pressure within said member.

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